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The !preload Command: Pre-Load PCell Sub-Masters

Syntax: !preload archive
Suppose that one has a collection of pcell sub-master Xic cells that have been imported from a foreign OpenAccess tool such as Virtuoso. These are assumed to not be portable pcells. One would like to use these cells to resolve pcells when reading directly from the OpenAccess database. There are two issues: 1) the system needs to know that these cells are available, and 2) one has to remap the cell names. The first issue is fixed simply by making the sub-masters available through the library mechanism. The second issue is due to the simple naming convention of the sub-master instantiations, which suffixes the pcell name with ``$$" followed by an integer. The integer is a count of when the cell was generated, and is consistent with the design output at the time, but there is no guarantee the the names are consistent with the design at other times.

This command will read a collection of cells into a temporary symbol table. Those that are pcell sub-masters have the property strings entered into the internal pcell database, under the existing cell name. This will cause the correct cell name to be associated with a given parameter set. The cells are not saved, but the entries in the pcell table persist so that resolution, when reading OpenAccess or otherwise, will reference the correct cells. The cell collection must be available through an open library, and this function must be run before loading the design.

The argument is either a path to a directory containing native pcell sub-master cells, or a path to an archive file that contains the cells. This capability is also available with the RegisterSubMasters script function.


next up previous contents index
Next: Rulers Up: Parameterized Cells Previous: The !rmpcprops Command: Remove   Contents   Index
Stephen R. Whiteley 2018-08-14